Michigan Gov. Rick Snyder and fellow Republicans are backing controversial "right-to-work-for-less" legislation at the behest of corporate donors who see it as a way to weaken unions in this stronghold of the American auto workers.

President Obama denounced the bill, calling it "the right to work for less." A White House spokesman said: "The president believes our economy is stronger when workers get good wages and good benefits, and he opposes attempts to roll back their rights. Michigan - and its workers' role in the revival of the US automobile industry - is a prime example of how unions have helped build a strong middle class and a strong American economy."

AFT notes that so-called "right-to-work" laws drive down wages for all workers by an average of $1,500 a year-whether they are in a union or not.